1. Field of the Invention
A backlight unit and a display apparatus having the same consistent with the present invention relate to emitting, in sequence, light sources.
2. Description of the Related Art
Recently, as various demands for a display apparatus increases, various flat panel display apparatuses such as a liquid crystal display (LCD), a plasma display panel (PDP), an electro luminescent display (ELD), and a vacuum fluorescent display (VFD), etc. have been used. Especially, among these flat panel display apparatuses, a display apparatus using a liquid crystal panel has been used widely because the display apparatus is capable of operating under low electric power, and has a superior display property.
However, since the display apparatus using the liquid crystal panel is a non-emissive type, and only adjusts the amount of light transmitting a liquid crystal, the display apparatus needs a light source supplying a uniform light to a total screen.
In general, a cathode fluorescent lamp emitting a white light such as a cold cathode fluorescent lamp (CCFL), a hot cathode fluorescent lamp (HCFL), or the like can be used as the light source.
When the display apparatus using the liquid crystal panel is employed for a television to mainly display a moving image, a slow response speed of the liquid crystal causes a blurring phenomenon that a boundary of the image is unclear and hazily displayed.
Accordingly, a conventional scanning-type display apparatus may be used which employs a scanning method of driving a lot of lamps in sequence to correspond to a response speed of the liquid crystal to improve the blurring phenomenon generated in the image.
In the conventional scanning-type apparatus, a backlight unit includes a lot of lamps positioned facing a rear surface of the liquid crystal panel and connected in parallel. Generally, herein a plurality of lamps refer to a single unit block, and a large number of lamps refers to n unit blocks from a first block to an Nth block.
Also, n scanning signals having a predetermined frequency (for example, 60 Hz to 120 Hz) are generated to drive the backlight unit so that the lamps provided to the n unit blocks can be respectively turned on and off in sequence.
In general, the scanning signal is generated by a digital circuit such as a field programmable gate array (FPGA), a microcomputer integrated circuit, or the like. Accordingly, to drive the lamps of the backlight unit based on the scanning signal of the digital signal, a digital circuit such as the FPGA or the microcomputer integrated circuit is needed. However, the digital circuit has a complicated configuration, and the cost of the component is high, which increases the ultimate cost of the product.